Sheet materials having one or more fibrous surfaces are well known to those in the art. Examples of such materials are nonwoven web materials. In recent years nonwoven web materials such as, for example, meltblown and spunbonded materials, have gained significant market recognition and acceptance as compared to more conventional woven textile materials when the material is to be used in a "disposable" application. As used herein, the term "disposable" is intended to include applications where a product is designed to be used once or a very limited number of times and then thrown away. Acceptance of the nonwoven web materials has been, at least in part, due to the highly favorable costs associated with the manufacture of the nonwoven web materials as compared to conventional weaving processes. For example, nonwoven web materials have significantly penetrated the manufacture of products such as disposable diapers, training pants, hospital gowns, surgical gowns, surgical drapes and environmentally protective clothing such as chemically protective and biologically protective clothing.
In spite of the penetration of the identified markets and others by nonwoven web materials, many products in these areas highly desire, if not require, the garment or other item to maintain a barrier against a given substance. This desirable attribute has virtually become a requirement in the medical area with the advent of the AIDS virus and the concomitant wish for doctors to remain isolated from patients' bodily fluids and vis versa. Typically, conventional nonwoven web material with its generally open porous structure cannot provide an absolute barrier against fluids such as gases and liquids or, for that fact, for small solid particulates such as dust or viruses.
Such an absolute barrier can typically only be obtained through the utilization of a film layer desired to act as a barrier to the substance or substances which are to remain isolated. Products formed from film layers have, indeed, been utilized. Unfortunately, such film-formed products suffer from a number of deficiencies. First, the product generally appears to be of a very cheap nature. Secondly, the product may well be quite uncomfortable as a result of the harsh hand or feel of a plastic film. Further, the product may well add to the discomfort of the wearer because plastic films typically cannot pass water vapor and the wearer's perspiration tends to build-up on the inside of the garment or on the wearer because it has no readily available avenue of escape.
In order to overcome the deficiencies of a garment manufactured from a film, those in the art have laminated films to nonwoven materials. Such a lamination, with the nonwoven web material being on an outer surface, gives the resultant composite a very pleasant hand. Furthermore, if the film is apertured, for example, microaperatured so that water vapor can pass through it, the comfort of the wearer is improved significantly. If the apertures in the film are small enough, the composite can be designed to be a generally effective barrier against quite a number of substances. While garments formed from nonwoven/film laminates have enjoyed success, a drawback associated with them is the increased cost of manufacture associated with the lamination process. In other words, to get the benefits of both a film material and a nonwoven material not only must both materials be used but the two must be married together in a costly lamination process. This places products made from such a laminate at a competitive disadvantage.
Accordingly, those of skill in the art have been searching for a process or processes where a liquid impermeable sheet can be formed which has a fibrous surface with a soft cloth-like hand and which avoids the costs associated with lamination and the utilization of disparate materials.